The use of Roll Your Own (RYO) cigarettes has increased dramatically in the UK, New Zealand, Australia, Canada and Europe where prices of factory made (FM) cigarette have increased through taxation and restrictive marketing. In the UK 27% of smoker use RYO cigarettes;the US prevalence is about 6.7%. Most RYO smokers choose these cigarettes because they are cheaper than FM cigarettes, however, others use RYO because they are perceived to be less harmful, offer more flexibility and control of content, and they have cultural appeal. In spite of widespread use in other countries and the possibility of increased domestic use, very little is known about smokers of RYO cigarettes, the consistency of the RYO cigarettes they use, how they are smoked, the toxin exposure from their use and what happens when people switch from FM cigarette use to RYO use. These questions are addressed in the proposed research application. RYO users will be classified as mixed RYO/FM, exclusive RYO or exclusive FM smokers. While being observed in the laboratory, RYO smokers will prepare 20 cigarettes with the tobacco and rolling equipment they ordinarily use. These cigarettes will be analyzed for tobacco content, weight and overall product consistency. In another study, exclusive RYO smokers will be compared to exclusive FM smokers on baseline measures of chronic tobacco exposure (i.e., NNAL and 1- HOP, plasma cotinine). Acute exposure to carbon monoxide (CO) and nicotine will be assessed, as will measures of puffing topography and inhalation patterns. Subjects will smoke in the laboratory under three conditions: normal cigarette consumption;after verified tobacco abstinence of at least 12 hr;and after intensive smoking in the hour before the experimental session. Mixed RYO/FM smokers will be tested as they consume their usual FM brand and RYO cigarettes under the same conditions. These laboratory manipulations are known to cause "compensation" (changes in smoking behavior) in FM cigarettes but these conditions have not yet been tested with RYO cigarette use. To determine changes in exposure consequences of switching to RYO use, a cross over study will be used where exclusive FM smokers (after baseline assessments) will smoke RYO cigarettes for 15 days. Overall, these studies will provide a current assessment of the use characteristics of RYO smokers and provide important information about health and risk consequences of RYO use. This information is important for current RYO smokers and FM smokers who are contemplating RYO use. The data will also inform policy relevant to advertising restrictions, marketing and taxation of RYO cigarettes and the relative harmfulness of RYO to FM cigarettes. PUBLIC HEALTH RELEVANCE: The proposed research will be the first systematic human laboratory evaluation of Roll Your Own (RYO) cigarettes. The research will answer fundamental questions about the nature of RYO cigarettes and their consumers, how RYO cigarettes compare to conventional cigarettes in terms of smoking behavior and toxin exposure, and what the consequences are of switching from conventional to RYO cigarettes. The results will inform RYO smokers and policy makers about the relative risk of this growing trend in cigarette smoking.